Impact head for setting mine-roof bolts



,Nov. 1, 1960 L. R. BICE 2,

. ,IMPACTHEAD FOR SETTING MINE-ROOF sows Filed May 7, 1959 {a I INVENTOR LLOYDRB/CE Attainey United States Patent IMPACT HEAD FOR SETTING MINE-ROOF BOLTS Lloyd R. Bice, Mulga, Ala., assignor to United States Steel Corporation, a corporation of New Jersey Filed May 7, 1959, Ser. No. 811,627

2 Claims. (Cl. 1-49.9)

This invention relates to an improved impact head or dolly for setting mine roof bolts of the slotted type.

Roof bolts are set in holes drilled upwardly in a mine roof. A slotted roof bolt must be driven forcibly into the hole, since the slotted portion must be expanded by the action of a wedge inserted in the slot to anchor the bolt. Commonly the bolt is set with the same percussive drill used to drill the hole. To set the bolt, a stub steel and a dolly are installed on the drill in place of the usual drill steel. The dolly receives the lower end of the bolt, whereupon the drill is operated to force the bolt into the hole. The hole is drilled with a hollow drill steel, and cuttings are removed during the drilling operation by applying suction to the bore of the drill steel. Subsequently the cuttings are transferred through a flexible suction tube to a suitable collector. Heretofore, as far as I am aware, no means have been provided for carrying away dust generated in setting the bolt. Although the dust problem is less acute than during dn'lling, enough dust is generated to be objectionable.

An object of the present invention is to provide an improved dolly which has means for collecting and carrying away dust generated as a slotted roof bolt is set.

A further object is to provide an improved dolly which has a cup for collecting dust generated as a slotted roof bolt is set and passages leading from the cup to the bore of a hollow stub steel, whereby suction can be applied to the passages and cup.

'In accomplishing these and other objects of the invention, I have provided improved details of structure, a preferred form of which is shown in the accompanying drawing, in which:

Figure 1 is a side elevational view of a portion of a percussive drill which carries a dolly constructed in accordance with my invention;

Figure 2 is a top plan view of the dolly on a larger scale; and

Figure 3 is a vertical sectional view of the dolly.

Figure 1 shows a portion of a conventional percussive drill used for drilling a hole H upwardly in a mine roof R. An upwardly extending hollow stub steel 12 is installed in the drill in place of the usual drill steel. The upper end of the stub steel carries a dolly 13 constructed in accordance with my invention. The dolly in turn carries a conventional slotted roof bolt 14, whose slot 15 contains a wedge :16. The drill is operated in the usual way to drive the bolt upwardly into the hole and ultimately to expand the slotted portion and thus anchor the bolt. The drill is equipped with conventional means, not shown, for applying suction to the bore of the drill steel.

As shown in Figure 3, dolly 13 includes a cylindrical body whose upper end carries an enlargement 17. The body has the usual sockets 18 and 19 which extend from its lower and upper faces for receiving the upper end of the stub steel 12 and the lower end of the roof bolt 14 respectively. The enlargement 17 is counterbored to form a cup 20. A plurality of passages 21 extend downwardly from the bottom of cup 20 and obliquely inwardly into communication with the lower socket 18. The suction means of the drill is operated as the bolt is set, whereby dust generated during this operation is drawn into cup 20, and thence through passages 21 and the bore of the stub steel 12. From there the dust is transferred to the same collector as cuttings produced as the hole is drilled.

While I have shown and described only a single embodiment of my invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

I claim:

1. An impact head adapted to be used with a percussive drill and a hollow stub steel for setting a mine roof bolt of the slotted type, said head comprising a cylindrical body having lower and upper sockets extending from its lower and upper faces to receive the stub steel and roof bolt respectively, said body also having a cup in its upper face and passages extending from the cup into communication with said lower socket, whereby suction applied through the bore of the stub steel draws dust into said cup and passages.

2. The combination, with a percussive drill and a hollow stub steel carried thereby, of an impact head for setting a mine roof bolt of the slotted type, said head comprising a cylinrdical body having lower and upper sockets extending from its lower and upper faces, said lower socket receiving the upper end of said stub steel, said upper socket being adapted to receive the lower end of the bolt, said body also having a cup in its upper face and passages extending from the cup into communication with said lower socket, whereby suction applied through the bore of the stub steel draws dust into said cup and passages.

References Cited in the file of this patent UNITED STATES PATENTS 230,145 Moses July 20, 1880 666,799 Buckwalter J an. 29, 1901 1,775,917 Rudlin Sept. 16, 1930 1,896,979 Smith Feb. 7, 1933 2,122,507 Ball July 5, 1938 2,359,971 Curtis Oct. 10, 1944 

